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./ - example with defaults set for minimal time spent in garbage collection
#! /bin/sh
# ==================================================================
# ______ __ _____
# /_ __/___ ____ ___ _________ _/ /_ /__ /
# / / / __ \/ __ `__ \/ ___/ __ `/ __/ / /
# / / / /_/ / / / / / / /__/ /_/ / /_ / /
#/_/ \____/_/ /_/ /_/\___/\__,_/\__/ /_/
# Multi-instance Apache Tomcat installation with a focus
# on best-practices as defined by Apache, SpringSource, and MuleSoft
# and enterprise use with large-scale deployments.
# Credits:
# Google -> Couldn't survive without it
# -> Community support
# SpringSource -> Specifically best-practices and seminars (Expert Series)
# Based On:
# Created By: Terrance A. Snyder
# URL:,
# Best Practice Documentation:
# Looking for the latest version?
# github @
# ==================================================================
# discourage address map swapping by setting Xms and Xmx to the same value
# Increase maximum perm size for web base applications to 4x the default amount
export CATALINA_OPTS="$CATALINA_OPTS -XX:MaxPermSize=256m"
# Reset the default stack size for threads to a lower value (by 1/10th original)
# By default this can be anywhere between 512k -> 1024k depending on x32 or x64
# bit Java version.
# Oracle Java as default, uses the serial garbage collector on the
# Full Tenured heap. The Young space is collected in parallel, but the
# Tenured is not. This means that at a time of load if a full collection
# event occurs, since the event is a 'stop-the-world' serial event then
# all application threads other than the garbage collector thread are
# taken off the CPU. This can have severe consequences if requests continue
# to accrue during these 'outage' periods. (specifically webservices, webapps)
# [Also enables adaptive sizing automatically]
# This is interpreted as a hint to the garbage collector that pause times
# of <nnn> milliseconds or less are desired. The garbage collector will
# adjust the Java heap size and other garbage collection related parameters
# in an attempt to keep garbage collection pauses shorter than <nnn> milliseconds.
export CATALINA_OPTS="$CATALINA_OPTS -XX:MaxGCPauseMillis=1500"
# A hint to the virtual machine that it.s desirable that not more than:
# 1 / (1 + GCTimeRation) of the application execution time be spent in
# the garbage collector.
# The hotspot server JVM has specific code-path optimizations
# which yield an approximate 10% gain over the client version.
# Disable remote (distributed) garbage collection by Java clients
# and remove ability for applications to call explicit GC collection
export CATALINA_OPTS="$CATALINA_OPTS -XX:+DisableExplicitGC"
# Check for application specific parameters at startup
if [ -r "$CATALINA_BASE/bin/" ]; then
echo "Using CATALINA_OPTS:"
for arg in $CATALINA_OPTS
echo ">> " $arg
echo ""
echo "Using JAVA_OPTS:"
for arg in $JAVA_OPTS
echo ">> " $arg
echo "_______________________________________________"
echo ""

poolebu commented May 22, 2013

I am so grateful for this, it completely changed my production server's performance, and opened up a lot of useful knowledge. Thank you

zmirc commented Jul 22, 2013

Thank you so much!

This is just what I was looking for—thanks, @terrancesnyder ! One comment/question: you say you want to "discourage address map swapping by setting Xms and Xmx to the same value" but then use different vales in your script (-Xms64m & -Xmx512m), a couple of lines later; was this an error, or did you change your mind about the ideal values and forget to update the comment?

Avec112 commented Mar 10, 2014

Thanks for sharing.

With Java 7, I see a "Stack Size Too Small" and then tomcat refuses to startup. Recommended size is 228k.

Thanks. Very useful.
I 've found the same message from tomcat "The stack size specified is too small, Specify at least 228k", so i need to increase the Xss by using this value " -Xss256k" and to prevent a permgen space i use a different value : "-XX:MaxPermSize=512m"

scduvv2 commented Dec 14, 2014

Thanks a lot

This is very cool. It increases my tomcat performance significantly. Thanks.

Thanks a lot!

jouna commented Jun 3, 2015

Thanks for sharing!



Thanks .. Really very helpful..

nickk75 commented May 18, 2016

Thanks for the knowledge sharing dude, much appreciated

wimco commented Jun 21, 2016

Hi Guys i have installed Alfresco community 5.0.e on Ubuntu 14.04 LTS and i cant find file. What can I do i want to run javascript debugger


The various CATALINA_OPTS such as -Xms , Xmx, XX:MaxPermSize seem to be independant of physical RAM.
Is it right ?
What are the default values (for Tomcat 7) ?

It does not work for me
Creating with just export CATALINA_OPTS="$CATALINA_OPTS -Xmx512m" in it crashes tomcat7 on start.
$CATALINA_OPTS is not defined in my standard tomcat7 installation on Debian Jessie.
Should I define it somewhere ?

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